1. Field of the Invention
The present invention relates generally to optical lens, and particularly to so-called "Selfoc" (TM) lens also known as graded index (GRIN) lens. More particularly still, it relates to such class of lens which are configured at one end thereof for termination and/or connection of optical fibers to provide reduced back-reflection to the fiber.
2. Prior Art of the Invention
U.S. Pat. No. 4,268,112 granted May 19, 1981 to Peterson discloses several embodiments based on the optical transmission characteristics of a Luneberg lens for terminating optical fibers, where the fiber is inserted into an axial bore at the tapered end of an elliptical bead having a graded index of refraction where the fiber end lies at a focal point of the bead. The entire structure is axially symmetrical.
U.S. Pat. No. 4,490,020 granted Dec. 25, 1984 to Sakaguchi et al discloses a cylindrical lens the width of the end portion of which continuously decreases towards its tip at least in a plane parallel to the optical axis of the output light from a semiconductor laser. The structure, again, is axially symmetrical.
U.S. Pat. No. 4,962,988 granted Oct. 16, 1990 to Swann discloses several graded index glass rod lens having ends for joining to optical fibers, which ends are tapered down radially, the taper being axially symmetrical. The profile of the tapered portion of the lens may be frusto-conical, convex or concave, and the optical fiber end being terminated by the lens is co-axial with the lens axis.
The above U.S. patents are incorporated herein by reference.